JP2000281779A - Production of low-viscosity polyphenylene ether - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce a low-viscosity polyphenylene ether while inhibiting the formation of a fine powder by adding an alkali to a methanol cleaning solution of polyphenylene ether particles to subject an aromatic compound and methanol-water to liquid-liquid separation, separating methanol by distillation, and circulating it in the process. SOLUTION: A low-viscosity polyphenylene ether having an intrinsic viscosity of 0.38 or lower is synthesized by the oxidative polymerization of a phenolic compound in the presence of an aromatic compound solvent, a copper compound, and an amine. Methanol is added to the resultant aromatic compound solution to form a slurry, which is sujected to solid-liquid separation. Thus obtained polyphenylene ether particles are washed with methanol. An alkali in an amount of 0.1-1.8 wt.% (based on water and the filtrate) is added to the filtrate containing an aromatic compound, polymerization by-products, an amine and metahol to subject the aromatic compound and methanol to liquid-liquid separation. Methanol, water and an amine are separeated by distillation, and a distillate mainly comprising methanol is circulated in the process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an intrinsic viscosity of 0.38.
The present invention relates to the following method for producing a low-viscosity polyphenylene ether having excellent melt flow characteristics.

[0002]

2. Description of the Related Art Polyphenylene ether is an engineering plastic having excellent mechanical properties, heat resistance properties, electrical properties, etc., but has poor flow properties upon melting and has a problem in moldability and is usually represented by polystyrene. It is used as a composition with other resins. However,
In order to take advantage of the excellent properties of polyphenylene ether, it is necessary to increase the composition ratio of polyphenylene ether, and under the recent demand for high product performance, it is necessary to improve the flowability of polyphenylene ether itself during melting It has become. To solve this problem, a method of adjusting the molecular weight distribution during the polymerization reaction (Japanese Patent Laid-Open No. 6-212072)
However, controlling the molecular weight distribution actually involves significant process changes.

Further, a method is disclosed in which polyphenylene ether having a low viscosity is simultaneously added during the production of an extruded mixture of a composition (Japanese Patent Application Laid-open No. 4-342762). .38 or less polyphenylene ether must be produced. At this time, in the step of adding methanol to the aromatic compound solution of the polyphenylene ether after the polymerization reaction to precipitate the polyphenylene ether particles, a large amount of fine powder was generated, which hindered the solid-liquid separation step and was obtained. Special extruders must be used for mixing the products. In addition, after the polyphenylene ether slurry is subjected to solid-liquid separation, poor separation occurs when the filtrate is separated into an aromatic compound and methanol-water, and a distillate containing methanol precipitates through a distillation and recovery step. At present, it is difficult to reuse in the chemical conversion process.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to find a technique for efficiently reusing a filtrate obtained after solid-liquid separation of a polyphenylene ether slurry for aromatic precipitation, and at the same time, to suppress the production of fine powder, and to efficiently and uniquely identify the technique. An object is to produce a low-viscosity polyphenylene ether having a viscosity of 0.38 or less.

[0005]

Means for Solving the Problems As a result of diligent studies, the present inventors have found that when producing polyphenylene ether (PPE) having an intrinsic viscosity of 0.38 or less, many by-products are formed, which are fragrant in the aqueous extraction of the filtrate. The liquid-liquid separation of the aromatic compound and methanol-water is inferior. As a result, a large amount of the aromatic compound is entrained in the aqueous methanol, and is recycled together with methanol as a distillate for purification in the polymer precipitation to increase the generation of fine powder. I found what I was doing.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to (a) a method in which one or two or more phenol compounds are oxidatively polymerized in the presence of an aromatic compound solvent, a copper compound and an amine to obtain a low intrinsic viscosity of 0.38 or less. Synthesizing a polyphenylene ether having a viscosity; (b) adding methanol to an aromatic compound solution of an aromatic compound of the polyphenylene ether obtained in (a) to precipitate polyphenylene ether particles;
(C) a step of subjecting the polyphenylene ether slurry obtained in (b) to solid-liquid separation, and further washing the particles of polyphenylene ether with methanol; (d) an aromatic compound, a polymerization reaction by-product obtained in (c); In a filtrate containing amines and methanol, 0.1 to 1.8 with respect to water and the filtrate.
(e) a step of liquid-separating an aromatic compound and methanol-water in a liquid phase, and (e) continuously drying the polyphenylene ether slurry obtained in (c) under a nitrogen stream to obtain a polyphenylene ether powder. And the methanol, water and amines obtained in (f) and (d) are separated by distillation to obtain a distillate containing methanol as a main component, as shown in (b).
And a method for producing a low-viscosity polyphenylene ether comprising a total of six steps of recycling to step (c).

[0007] The polymerization reaction solvent used in the polymerization of the present invention is a solvent containing 50% or more, preferably 70% or more of xylene and / or toluene.

The polyphenylene ether referred to in the present invention is:
It is represented by a repeating unit of the general formula (1).

Embedded image (Wherein, R1 represents a primary or secondary alkyl group, an aryl group, an aminoalkyl group, a halogen atom, a halohydrocarbon group, a hydrocarbonoxy group or a halohydrocarbonoxy group, and R2 represents a hydrogen atom Represents a primary or secondary alkyl group, a halogen atom, a halohydrocarbon group, a hydrocarbonoxy group or a halohydrocarbonoxy group.)

Typical examples are poly (2,6-dimethyl-1,4-phenylene) ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether, poly (2,6- Diethyl-1,4-phenylene) ether, poly (2-ethyl-6-n-propyl-1,4-phenylene) ether, poly (2,6-di-n-propyl-1,4-phenylene) ether, Poly (2-methyl-
6-n-butyl-1,4-phenylene) ether, poly (2-ethyl-6-isopropyl-1,4-phenylene) ether, poly (2-methyl-6-chloroethyl-)
1,4-phenylene) ether, poly (2-methyl-6)
-Hydroxyethyl-1,4-phenylene) ether and the like, and polyphenylene obtained by combining 2,6-dimethylphenol with one or both of 2,3,6-trimethylphenol and o-cresol as copolymer components Ether copolymers and the like.

In the present invention, a polymer can be obtained by performing a polymerization reaction in a solution using air or diluted oxygen or pure oxygen as an oxygen source in the presence of a copper compound and amines. Any known method such as a continuous reaction or a batch reaction may be used to obtain a polymer solution of the above.

The reaction solution after the polymerization reaction comprises ethylenediamine or one or more of its compounds, an aqueous solution (a) containing a reducing agent, and a polymerization reaction solution (b).
The reaction is stopped by catalytic mixing at a ratio of 0.1: 1 to 5: 1.

After the reaction is stopped, in order to perform a precipitation treatment, the polymerization reaction solution is adjusted to 2 to 35% by weight with respect to the contained polymer, and methanol is added 0.2 to 5 times to the solvent. , To precipitate the polymer. Precipitation can be performed by any known precipitation method such as continuous precipitation and batch precipitation, except that a reciprocating stirrer is used for stirring.

The precipitated polymer is filtered by a known method such as centrifugal filtration or continuous filtration.

The filtrate is 0.1 to 0.1 parts based on water and water + filtrate.
In the range of 0.18 wt%, alkalis are added and mixed. The alkalis mentioned here are represented by alkali metals and their compounds. If the addition amount is smaller than this, poor separation is caused in the liquid-liquid separation in the subsequent step, and if it is larger than this, the pH is increased and the recovery distillation is hindered.

In order to separate the filtrate after filtration into the aromatic organic solvent used in the polymerization reaction and methanol + water, any known liquid-liquid separation method may be used. Most preferably, a liquid-liquid separator is used.

Methanol is separated by distillation from the methanol-water obtained by liquid-liquid separation, and recovered and used in the precipitation step.

The slurry obtained by the solid-liquid separation is dried to obtain a polyphenylene ether powder. The drying method is not particularly limited as long as it is a known method. However, it is preferable to continuously dry using a stirring dryer under a nitrogen stream.

[0018]

EXAMPLES The present invention will be described below with reference to specific examples, but the present invention is not limited to these examples.

The ratio of particles of 140 mesh or less in the dry powder of polyphenylene ether is determined according to JIS standard (JIS Z8).
801). Using a 140 mesh sieve, TNK
After sieving with a sieve vibrator (manufactured by Tanaka Chemical Instruments) for 10 minutes, the weight not passing was measured. The state of the separated liquid after liquid-liquid separation was visually observed, and an aromatic organic solvent component of each separated liquid was analyzed by gas chromatography to confirm the state of separation.

Reference Example 1 (1) 2 kg of cupric bromide was dissolved in 35 kg of dibutylamine and 800 kg of toluene. In this catalyst solution,
200 kg of 2,6-dimethylphenol was added to 50 parts of toluene.
A solution dissolved in 0 kg was added. These mixed liquids were reacted at 40 ° C. in a reactor until the intrinsic viscosity reached 0.5 while sequentially measuring the intrinsic viscosity with a viscometer while supplying air. (2) After the reaction was stopped, the catalyst was removed from the reaction solution by contacting with water to obtain a polyphenylene ether polymerization reaction solution. (3) This polyphenylene ether reaction liquid was added to methanol, and precipitated and precipitated while stirring with a reciprocating stirrer. Thereafter, the liquid was separated by a solid-liquid separator to obtain a polymer wet solid, which was continuously dried under a nitrogen stream. Further, 20 kg of water and 100 g of sodium hydroxide were used for 100 kg of the obtained filtrate (0.085 W for the filtrate + water).
t%), and separated into toluene and methanol-water by a liquid-liquid separator. The separation was good. (4) Methanol is distilled and recovered from the obtained methanol-water and used as methanol for precipitation, and the above polymerization, precipitation, filtration, separation of the filtrate, and recovery of methanol are repeated.
1) -4) were repeated 5 times, and the separation state at the 5th time and the obtained polymer powder after drying were analyzed. Table 1 shows the results.

Example 1 (1) 2 kg of cupric bromide was dissolved in 35 kg of dibutylamine and 800 kg of toluene. In this catalyst solution,
200 kg of 2,6-dimethylphenol was added to 50 parts of toluene.
A solution dissolved in 0 kg was added. These mixed liquids were reacted at 40 ° C. in a reactor until the intrinsic viscosity reached 0.37 by sequentially measuring the intrinsic viscosity with a viscometer while supplying air. (2) After the reaction was stopped, the catalyst was removed from the reaction solution by contacting with water to obtain a polyphenylene ether polymerization reaction solution. (3) This polyphenylene ether reaction liquid was added to methanol, and precipitated and precipitated while stirring with a reciprocating stirrer. Thereafter, the liquid was separated by a solid-liquid separator to obtain a polymer wet solid, which was continuously dried under a nitrogen stream. Further, 20 kg of water and 153 g of sodium hydroxide were used for 100 kg of the obtained filtrate (0.130 W for the filtrate + water).
t%), and separated into toluene and methanol-water by a liquid-liquid separator. The separation was good. (4) Methanol is distilled and recovered from the obtained methanol-water and used as methanol for precipitation, and the above polymerization, precipitation, filtration, separation of the filtrate, and recovery of methanol are repeated.
1) -4) were repeated three times, and the separation state at the third time and the obtained polymer powder after drying were analyzed. Table 1 shows the results.

Example 2 According to the method of Example 1, the ultimate intrinsic viscosity was set to 0.35,
180 g of sodium hydroxide added in (3),
Example 1 was repeated. Table 1 shows the results.

Example 3 In the same manner as in Example 1, the ultimate intrinsic viscosity was set to 0.30,
180 g of sodium hydroxide added in (3),
Example 1 was repeated. Table 1 shows the results.

Example 4 According to the method of Example 1, the ultimate intrinsic viscosity was set to 0.27,
The sodium hydroxide added in (3) was 192 g,
Example 1 was repeated. Table 1 shows the results.

Comparative Example 1 In the method of Example 1, the ultimate intrinsic viscosity was set to 0.35,
With sodium hydroxide added in (3) being 102 g,
Example 1 was repeated. Table 1 shows the results.

Comparative Example 2 In the method of Example 1, the ultimate intrinsic viscosity was set to 0.27,
With sodium hydroxide added in (3) being 102 g,
Example 1 was repeated. Table 1 shows the results.

[0027]

[Table 1]

[0028]

According to the production method of the present invention, it is possible to obtain a polyphenylene ether having excellent intrinsic fluidity, a small amount of fine powder, and an intrinsic viscosity of 0.38 or less, which is extremely effective for mixing with other resins. It has become possible to provide a composition utilizing the excellent mechanical properties, heat resistance properties, and electrical properties.

Continuation of the front page (72) Inventor Chiharu Nishizawa 2-4-1, Hinagahigashi, Yokkaichi-shi, Mie F-term (reference) 4Y005 AA26 BC00

Claims (4)

[Claims] (A) a step of oxidizing and polymerizing one or more phenol compounds in the presence of an aromatic compound solvent, a copper compound and an amine to synthesize a polyphenylene ether having an intrinsic viscosity of 0.38 or less; (B) In the aromatic compound solution of polyphenylene ether obtained in (a),
Adding a non-solvent methanol to precipitate polyphenylene ether particles, (c) solid-liquid separation of the polyphenylene ether slurry obtained in (b), and further washing the polyphenylene ether particles with methanol;
(D) To the filtrate obtained in (c) containing the aromatic compound, the polymerization reaction by-products, the amines and methanol, 0.1 to 0.18 wt% of alkali relative to water and the filtrate is added. To extract the aromatic compound and methanol-water in liquid form, and to continuously dry the polyphenylene ether slurry obtained in (e) and (c) under a nitrogen stream to obtain a polyphenylene ether powder. A total of 6 steps, i.e., step (f), methanol, water and amines obtained in step (d) are separated by distillation, and a distillate containing methanol as a main component is recycled to steps (b) and (c). A method for producing a low-viscosity polyphenylene ether, comprising: 2. The method for producing a low-viscosity polyphenylene ether according to claim 1, wherein the aromatic compound solvent in the step (a) is a solvent containing 50% or more of xylene and / or toluene. 3. The method for producing a low-viscosity polyphenylene ether according to claim 1, wherein the polyphenylene ether in the step (a) has a structure represented by a repeating unit of the general formula (1). Embedded image (Wherein, R1 represents a primary or secondary alkyl group, an aryl group, an aminoalkyl group, a halogen atom, a halohydrocarbon group, a hydrocarbonoxy group or a halohydrocarbonoxy group, and R2 represents a hydrogen atom Represents a primary or secondary alkyl group, a halogen atom, a halohydrocarbon group, a hydrocarbonoxy group or a halohydrocarbonoxy group.) 4. The polyphenylene ether particles obtained in the step (e) have a fine powder having a mesh size of 140 mesh or less of 60 watts.
The method for producing a low-viscosity polyphenylene ether according to claim 1, which is at most t%.